I'm seeing massive RAM usage from Mail

I removed all mail accounts as I assumed it was something in an inbox taking up space, but even then, with no accounts other than iCloud (which contains zero messages and is never used) it's still ramping up to over 12G of ram usage

RAM usage with Mail running

As soon as mail is killed, the ram usage drops

RAM usage after mail is killed

Can anyone suggest where to start looking to identify why the RAM is being consumed like this and how to stop it?

OSX El Capitain 10.11.1 Macbook Pro 15" (Late 2011) 2.4ghz i7 with 16G of RAM

  • It's too bad that Apple can never seem to get Apple Mail right. :-( Just me (although I'm not alone), but it always seem to have trouble in one way or another. Dec 15, 2015 at 0:54
  • This question exhibits similar symptoms. In that question it looks like a integer rollover or casting bug causes Mail to think it has a massive number of messages to download does it's best to prepare by allocating all the memory it can find. It would be interesting to see your Mail Activity window.
    – alexkent
    Dec 15, 2015 at 22:33
  • I came home this evening to find my Macbook had updated to 10.11.2 Mail is now sitting at 35Mb RAM usage and stable I'll try adding some accounts back in and see if it is all clear Dec 16, 2015 at 18:06

1 Answer 1


First i would try and isolate the problem. Is Mail.app taking the same amount of memory on a new user account, im talking about a OS user account (Create a new test user in System preferences -> Users and Groups -> +)

In case it does i would look at "/Library/Application Support/Apple/Mail" and compare to a known good system (which only should contain Stationery) im suspecting you might have some plugins that make Mail.app use more memory than usual (i have 21k mail in my inboxes and it only uses 230mb).

If only your exciting user show this behavior, start by moving the ~/Library/Mail folder to like ~/Library/Mail.old and see if it stops using ram. Otherwise i would start looking for plugins or other applications that may interact with mail (there might be some internet plugins)

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